George thomas



N" me G THOMAS MECHANICAL TELEPHONE.

Patented Apr. 9,1889.

fill/11111 No. 401,227.r

Y @gvd fall @tm UNITED STATES PATENT EEICE.

GEORGE THOMAS, or NEW YORK, N. Y., AssIeNOE or ONE-ritmo 'ro JOSEPH u.sfMrsoN, OE SAME rnlcE.

MECHANICAL TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 401,227, dated April 9,1889.

Application tiled October l5, 1388. Serial No. 288,137. (No model.)

.To al?, whom t may con/cern.'

Be it known that I, GEORGE THOMAS, of the city, county, and State of NewYork, have invented new and useful Improvements in Acoustic Telephones,which are fully set forth in the following' specification andaccompanying drawings, in which- Figure l is a sectional view ofmyimproved telephone; Fig. 2, a side elevation of mouth Io and earpiece; Fig. 3, a sectional view ot diaplnagm-lmtton; Fig. 4, a plan ofdiaphragm;

Fig. 5, a perspective view of insulator for diaphragm.

This invention relates to acoustic telephones in which a line of wire`connects two vibrating diaphragms, either of which may receive ortransmit sound, and its purpose is to transmit sound more clearly thanhas been attained by telephones as heretofore constructed.

The general construction of my telephone is not broadly new; but with myimprovements a practical instrument of great etliciency is produced.

2 5 A represents the circular case of one of the receiving ortransmitting instruments, (it being adapted to either use,) inclosing abroad sound-chamber covered with diaphragm B, resting on the edge of thecase, which is again 3o covered by cover C, to which the transmittingend of the mouth and ear piece is to be applied by the person using' thetelephone; S and D, the combination mouth and earpiece.Transmitting-wire E is attached to diaphragm B by button F.

Case A is preferably made of wood, the rear part integral with tlatedges Il H, on which is laid. diaphragm Il and inclosing-case A, formingan air-chamber. Said diaphragm is tacked 4o at P to edges Il Il of caseA, not screwed. Diaphragm l5 is covered (except where the opening admitssound-waves) by cover C, attached to case A at the sides by screws O O.I prefer that the face of the diaphragm be free from the pressure of thecover, and to attain that purpose I raise the cover off of diaphragm Bby placing between cover C and diaphragm D small insulators R R, made ofrubber, papier-mache, or other suitable o material. The attachment ofcover C to case A at the side, keeping it clear Ot' the diaphragm,insures perfect clearness, distinctness, and purity of tone in words ormessages passing' through the diaphragm. If cover C is attached directlyto the face of the diaphragm, it will inevitably cause inequalityY andunreliability in the vibration of the dia.- phragm and a partialdeadening of tone and confusion of sound. ATo Aobviate this I protectthe face of the diaphragm from any press- 6o ure of cover C byinsulators It It, laid in several places on the face of the diaphragm,so as to lit squarely against the rear of cover C.

The construction of the combination mouthpiece and ear-piece is anotherimportant feature of my invention. It contains no diaphragm, and isadapted to be permanently attached to or detached from cover C at theopening thereof. It is made of papier-mache or other suitable material,and consists of two 7o outwardlyflaring parts, D and S. Inner chamber,S, having an Opening large enough to fully accommodate a persons mouth,is somewhat similar to a truncated cone with a part of its side cut ont,forming two communicating chambers or passages, N M. Outer chamber, D,tlares up and curves to cover a persons ear, while the mouth is placedat the opening of chamber S to talk against diaphragm B. Thiscombination mouth and ear 8o piece enables the sound-waves to bereceived with absolute accuracy, as the Waves naturally follow curvedchamber D after leaving diaphragm Il, and become audible and clear bythe time they reach the opening of chamberD. 8 5

In sending a message a part of the soundwaves is retiected by theinclined sides of space M, by which they are again reflected inconverging' lines on the center of the diaphragm, which strengthens thesound without 9o confusing it.

Diaphragm B consists of a sheet of tin between two sheets of leatheroid.They are glued together, forming a strong and durable resonant diaphragmwith greater elasticity and resonance than can be produced by any singlesubstance.

The transmitting Or connecting wire is attached at one end to onediaphragm and at the other to the other diaphragm, the attach- 10o mentbein made in each cascby means ot' button l", made of metal about twoinches in diarneter, fiat on one side and having an annular curve on theother, with tWo holes near 'the center, through which a steel, brass, orother suitable metal rod is passed and the two ends are riveted, forminga loop or hook.

The loop or hook on button F is passed through a hole punched in thecenter of the diaphraglnfand transmitting-wire E fastened to the loopgorhook, making a strong and durable hold on the diaphragm.

VhatI elailn as my invention, and desire to secure by Letters Patent, s-

1. A diaphragm for transmitting and receiving sound, composed ofleatheroid and tin, substantially as described.

GEORGE THOMAS.

Witnesses:

S. J. GORDON, JOHN W. RIPLEY.

